In order to close covered or outdoor parking lots, driveways and access roads, it is known to use barriers or gates equipped with corresponding actuating means, possibly also remote-controlled. Such barriers usually have a rigid, cast-iron base, which on its upper part has the shape of some kind of a spherical head and a correspondingly built barrier which can swing thereabout by 90 or approximately 90 degrees. Such a barrier or blocking device is known from the German Pat. No. 19 60 699.0. A blocking device, which is basically the same, is known from the German Pat. No. 27 12 546.8, but in this case however, the drawing illustrating the stable, cast-iron post has been eliminated. In this case also the barrier per se is swingable around an articulation located on the top of the post, whereby it is insured by a locking device that it can also be actuated manually, in a simple manner. Also known are the round- or square-based simple posts, blocking driveways or accesses, which are foldable and which permit access to the driveway or the entrance way by being folded down. The folding of the post is done manually in this case, and for this purpose the driver has to leave his vehicle. This is bothersome and disadvantageous, particularly in bad weather. Besides, it is also necessary to equip the barrier post with a lock, in order to prevent the folding down of the post by unauthorized persons, for passage.